How Did the Saint Become the Left Knight Commander’s Princess?

(Two male leads + a laid-back saintess bottom, Yiselan / a loyal dog-like left knight commander top, Lensor)

Note: An alternate-universe Western fantasy.

Yiselan was unconscious for three years after a great war. When he woke, he was told he had less than three years to live, so he set out for Anfeier Tu in search of a way to survive, only to encounter Lensor, the left knight commander who had betrayed him.

At first

Lensor: Let me explain.

Yiselan: What, you had your reasons? Okay, I understand. Let me go.

Lensor: No.

Later

Yiselan: What are you plotting?

Lensor: I love you. I want to be with you.

(I've wanted to write this for a long time. This is basically self-indulgent wish fulfillment. It's my first time writing, so please forgive my amateur prose. I hope you enjoy it! (=^▽^=))